First of all, when Ren is talking to Willard about the clubs back in Chicago where they go to dance and drink, what kind of age restrictions are placed on bars/clubs in Chicago? From my experience bars/clubs in the US have an age restriction of 21 (21 is the legal drinking age), so you either get ID'd at the door or you get in and get ID'd at the bar when getting drinks. Ren must be 17 or 18 as he is a senior in high school so he would not be able to get into bars/clubs and/or get drinks unless he had a fake ID and looked old enough to pass for 21. Is this the most likely explanation?

Secondly, when Ren gets angry and drives away to the empty mill or barn to dance to the music playing in his car he is seen to be drinking and smoking. Given that this is a town that won't even allow dancing, there is no way that he could buy alcohol or cigarettes (how old do you have to be to buy them in the US? In NZ it's 18, though it used to be 16). It is possible, though unlikely, that he brought them from Chicago and it is highly unlikely that someone older from his family bought them for him - especially with all the trouble Ren has caused the family. So, how did he the alcohol and cigarettes? Is it most likely that he took (stole) them from his family's place?

If anyone could shed some light on this I would be greatly appreciative :0)

Cheers

In most states, you have to be 18 to buy cigarettes, but I'm not sure what the age was at the time of the movie.